Abstract
With the experience accumulated from more than a century of silver applications in biology and medicine, physical development has become a powerful bioanalytical tool for marker amplification in blotting procedures, in situ hybridization, immunocytochemistry, histochemistry, and cytochemistry. Early, empirical techniques of silver impregnation followed by development in a reducing solution (chemical developer), or a solution which contained both silver reducers and silver salts (physical developer) were often capricious and suffered from unwanted silver precipitation caused by light and self-nucleation. To accommodate the modern demand for accurate physical development, various strategies have been devised to counter these problems. One approach has been to introduce organic colloids into the developer to keep the silver ions and reducer molecules apart, whilst excluding light by using a dark-room or by covering the solution. Albumen, gelatin, and complex polysaccharides have all been tested, but gum arabic is preferred. In addition, further control can be achieved by slowing down the rate of development with low pH and by changing from silver nitrate to silver lactate, which dissociates more slowly. Effective colloid protection in a physical developer is also provided by the inclusion of tungsten salts which can delay light-catalysed silver reduction and keep the developer clear for many minutes. The same result has been achieved by complexing the silver salt in the physical developer with very large organic molecules, restricting ionization. 'Light insensitive' commercial designer products have resulted. Probably no single formulation can satisfy all conditions of use, but with increased understanding of the mechanisms of physical developers a more flexible, user-friendly approach is anticipated.
| Original language | English |
|---|---|
| Pages (from-to) | 119-125 |
| Number of pages | 7 |
| Journal | Journal of Pathology |
| Volume | 186 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Oct 1998 |
| Externally published | Yes |
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Keywords
- Bioanalysis
- Colloidal gold
- Diaminobenzidine
- Physical developer
- Silver
ASJC Scopus subject areas
- Pathology and Forensic Medicine
Cite this
Silver development in microscopy and bioanalysis : Past and present. / Newman, Geoffrey R.; Jasani, Bharat.
In: Journal of Pathology, Vol. 186, No. 2, 10.1998, p. 119-125.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Silver development in microscopy and bioanalysis
T2 - Past and present
AU - Newman, Geoffrey R.
AU - Jasani, Bharat
PY - 1998/10
Y1 - 1998/10
N2 - With the experience accumulated from more than a century of silver applications in biology and medicine, physical development has become a powerful bioanalytical tool for marker amplification in blotting procedures, in situ hybridization, immunocytochemistry, histochemistry, and cytochemistry. Early, empirical techniques of silver impregnation followed by development in a reducing solution (chemical developer), or a solution which contained both silver reducers and silver salts (physical developer) were often capricious and suffered from unwanted silver precipitation caused by light and self-nucleation. To accommodate the modern demand for accurate physical development, various strategies have been devised to counter these problems. One approach has been to introduce organic colloids into the developer to keep the silver ions and reducer molecules apart, whilst excluding light by using a dark-room or by covering the solution. Albumen, gelatin, and complex polysaccharides have all been tested, but gum arabic is preferred. In addition, further control can be achieved by slowing down the rate of development with low pH and by changing from silver nitrate to silver lactate, which dissociates more slowly. Effective colloid protection in a physical developer is also provided by the inclusion of tungsten salts which can delay light-catalysed silver reduction and keep the developer clear for many minutes. The same result has been achieved by complexing the silver salt in the physical developer with very large organic molecules, restricting ionization. 'Light insensitive' commercial designer products have resulted. Probably no single formulation can satisfy all conditions of use, but with increased understanding of the mechanisms of physical developers a more flexible, user-friendly approach is anticipated.
AB - With the experience accumulated from more than a century of silver applications in biology and medicine, physical development has become a powerful bioanalytical tool for marker amplification in blotting procedures, in situ hybridization, immunocytochemistry, histochemistry, and cytochemistry. Early, empirical techniques of silver impregnation followed by development in a reducing solution (chemical developer), or a solution which contained both silver reducers and silver salts (physical developer) were often capricious and suffered from unwanted silver precipitation caused by light and self-nucleation. To accommodate the modern demand for accurate physical development, various strategies have been devised to counter these problems. One approach has been to introduce organic colloids into the developer to keep the silver ions and reducer molecules apart, whilst excluding light by using a dark-room or by covering the solution. Albumen, gelatin, and complex polysaccharides have all been tested, but gum arabic is preferred. In addition, further control can be achieved by slowing down the rate of development with low pH and by changing from silver nitrate to silver lactate, which dissociates more slowly. Effective colloid protection in a physical developer is also provided by the inclusion of tungsten salts which can delay light-catalysed silver reduction and keep the developer clear for many minutes. The same result has been achieved by complexing the silver salt in the physical developer with very large organic molecules, restricting ionization. 'Light insensitive' commercial designer products have resulted. Probably no single formulation can satisfy all conditions of use, but with increased understanding of the mechanisms of physical developers a more flexible, user-friendly approach is anticipated.
KW - Bioanalysis
KW - Colloidal gold
KW - Diaminobenzidine
KW - Physical developer
KW - Silver
UR - http://www.scopus.com/inward/record.url?scp=0031718713&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031718713&partnerID=8YFLogxK
U2 - 10.1002/(SICI)1096-9896(1998100)186:2<119::AID-PATH160>3.0.CO;2-M
DO - 10.1002/(SICI)1096-9896(1998100)186:2<119::AID-PATH160>3.0.CO;2-M
M3 - Article
C2 - 9924425
AN - SCOPUS:0031718713
VL - 186
SP - 119
EP - 125
JO - Journal of Pathology
JF - Journal of Pathology
SN - 0022-3417
IS - 2
ER -